Method and systems for indoor farming

ABSTRACT

A method of providing light to plants. The method comprises providing a plurality of plants within a room, grouping each plant of the plurality of plants into one of a plurality of groups of plants based at least in part on a desired total light integral (“TLI”) for each of the plurality of plants and providing the corresponding desired TLI to each plant of the plurality of plants by sequentially providing light to each of the plurality of groups of plants during a time period. For each group of plants, each plant has a substantially similar photoperiod and a sum of the photosynthetic photon flux densities (“PPFDs”) of all plants in the group of plants is substantially similar.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Application No.17/959,823 filed 4 Oct. 2022, which is a continuation of PatentCooperation Treaty (PCT) application No. PCT/CA2022/050404 having aninternational filing date of 17 Mar. 2022, which in turn claims priorityfrom, and for the purposes of the United States the benefit of 35 USC§119 in respect of, U.S. Application No. 63/163,573 filed 19 Mar. 2021.All of the applications in this paragraph are hereby incorporated hereinby reference.

TECHNICAL FIELD

This invention relates generally to indoor growth of plants and inparticular to methods for providing light to plants for indoor growth.

BACKGROUND

While plants have traditionally been grown outdoors, there is a growingtrend toward indoor growth of plants. As compared to traditionalfarming, indoor farming may use less land. Indoor farming allows for“vertical farming” in which crops can be stacked vertically within agrow room, thereby reducing the geographic footprint as compared totraditional farming. Indoor farming may also facilitate a reduction inthe use of pesticides and other potentially harmful chemicals byallowing for a pest-free environment.

In the absence of sunlight, indoor farming operations may employartificial lights.

ldeal growing conditions vary according to plant varietal. For example,for some plants, it may be ideal for a plant to receive betweenapproximately ten and 18 hours of light while requiring six to 14 hoursof darkness in a 24 hour cycle. The daily light integral (“DLI”) may beused to understand and evaluate the quantity of light a plant isreceiving. DLI is a cumulative measure of photosynthetically activeradiation (“PAR”). DLI may be defined as the quantity ofphotosynthetically active photons received by plants per area per day(with units of, for example, mol/m²/day). DLI may be increased byincreasing the photoperiod (e.g. the period of time during which lightis provided to the plant) and/or the photosynthetic photon flux density(“PPFD”) (e.g. the amount of light photons that a plant receives perarea per unit of time).

Once the DLI for a plant is determined, a lighting schedule (e.g.photoperiod and PPFD) may be chosen to achieve the desired DLI.Typically, all plants within a grow room are on the same schedule.However, since lights produce heat, maintaining all plants within a growroom on the same lighting schedule leads to large temperaturefluctuations. For example, maintaining all plants within a grow room onthe same light schedule may lead to periods of time where the grow roomoverheats (because all lights are turned on) and periods of time wherethe grow room may drop below a desired temperature (because all lightsare turned off). Temperature monitoring sensors and heating/coolingsystems may be employed to counteract these temperature fluctuations.However, such systems increase the cost to build and operate a growroom.

There is a general desire to provide systems and methods for growingplants indoors with reduced energy consumption and/or reduced cost.There is a general desire to provide systems and methods for growingplants indoors without temperature management systems (e.g. temperaturemeasurement and/or heating/cooling systems) or with reduced reliance onsuch temperature management systems thereby allowing for less expensiveand/or less sophisticated temperature management systems to be employed.

The foregoing examples of the related art and limitations relatedthereto are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the drawings.

SUMMARY

One aspect of the invention provides a method of providing light (e.g.photosynthetically active photons) to plants. The method comprisesproviding a plurality of plants within a room, grouping each plant ofthe plurality of plants into one of a plurality of groups of plantsbased at least in part on a desired total light integral (“TLl”) foreach of the plurality of plants for a time period and providing thecorresponding desired TLI to each plant of the plurality of plants bysequentially providing light to each of the plurality of groups ofplants during the time period. For each group of plants, each plant hasa substantially similar photoperiod and a sum of the photosyntheticphoton flux densities (“PPFDs”) of all plants in the group of plants issubstantially similar.

In some embodiments, grouping each light of a plurality of lights intoone of a plurality of groups of lights wherein each group of lightscorresponds to one of the plurality of groups of plants within the room.

In some embodiments, each group of lights is arranged to provide photonssubstantially only to its corresponding group of plants.

In some embodiments, the method comprises maintaining a cumulative rateof heat output of the plurality of lights approximately constant duringthe time period. In some embodiments, the method comprises sequentiallyproviding light to each of the plurality of groups of plants during atime period comprises sequentially turning on each group of lights ofthe plurality of groups of lights for a sub-period of time.

In some embodiments, at least some of the sub-periods of time overlap.In some embodiments, each of the sub-periods of time is approximatelyequal in magnitude. In some embodiments, at least two of the sub-periodsof time have different magnitudes. In some embodiments, the combinedmagnitude of the sub-periods of time is approximately equal to the timeperiod. In some embodiments, each group of lights is turned on only onceduring the time period. In some embodiments, one or more groups oflights is turned on multiple times during the time period.

In some embodiments, sequentially providing light to each of theplurality of groups of plants during a time period comprises selectivelyturning on a first group of lights of the plurality of groups of lightsfor a first sub-period of time while selectively turning off a secondgroup of lights of the plurality of groups of lights for the firstsub-period of time.

In some embodiments, sequentially providing light to each of theplurality of groups of plants during a time period comprises selectivelyturning on a first group of lights of the plurality of groups of lightsfor a first sub-period of time while selectively turning off a secondgroup of lights of the plurality of groups of lights for the firstsub-period of time and selectively turning on the second group of lightsfor a second sub-period of time while selectively turning off the firstgroup of lights for the second sub-period of time.

In some embodiments, a plurality of lights are moveable between aplurality of locations and in each location the plurality of lightsprovides photos to a corresponding a group of plants of the plurality ofplants within the room. In some embodiments, in each location, theplurality of lights are arranged to provide photons substantially onlyto the corresponding group of plants.

In some embodiments, a cumulative rate of heat output of the pluralityof lights is maintained approximately constant during the time period bysequentially moving the plurality of lights to each location for acorresponding sub-period of time.

In some embodiments, the method comprises selectively moving theplurality of lights to a first location for a first sub-period of timeand a second location for a second sub-period.

In some embodiments, each group of plants is separated from one or moreother groups of plants in a substantially horizontal direction. In someembodiments, each group of plants is separated from one or more othergroups of plants in a substantially vertical direction. In someembodiments, at least one of the groups of plants is arranged invertically spaced apart rows of a rack in the room. In some embodiments,at least one of the groups of plants is arranged across rows of multipleracks. In some embodiments, at least one of the groups of plants isarranged across rows of multiple racks at the same height. In someembodiments, at least one of the groups of plants comprises plants ofonly a portion of a row of a rack. In some embodiments, at least one ofthe groups of plants comprises plants spaced apart throughout the room.In some embodiments, at least one of the groups of plants comprisesplants spaced apart at various heights throughout the room.

In some embodiments, the room is separated into a plurality of sectionsin a horizontal plane and at least one of the groups of plants comprisesplants located in each of the plurality of sections. In someembodiments, the at least one of the groups of plants comprises plantslocated at various heights in each of the plurality of sections.

In some embodiments, the time period is approximately equal to 24 hours.

In some embodiments, the room is arranged to substantially preventexternal light from entering the room. In some embodiments, the room isarranged to substantially prevent external natural light from enteringthe room.

In some embodiments, for each group of plants, the photoperiods of theplants of said group vary by less than 20%. In some embodiments, foreach group of plants, the photoperiods of the plants of said group varyby less than 10%. In some embodiments, for each group of plants, thephotoperiods of the plants of said group vary by less than 5%. In someembodiments, the sum of the PPFDs for each group varies by less than20%. In some embodiments, the sum of the PPFDs for each group varies byless than 10%. In some embodiments, the sum of the PPFDs for each groupvaries by less than 5%.

In some embodiments, a sum of the photoperiods of all of the groups ofplants is approximately equal to or greater the time period. In someembodiments, the sum of the photoperiods of all of the groups of plantsis within 10% of the magnitude of the time period. In some embodiments,wherein a sum of the photoperiods of all of the groups of plants iswithin 5% of the magnitude of the time period.

In some embodiments, grouping each of the plurality of plants into aplurality of groups of plants comprises nominally grouping each of theplurality of plants into a plurality of groups of plants.

In some embodiments, the plurality of plants comprises at least twodifferent plant varietals. In some embodiments, the method comprisesgrouping each of the plurality of plants into the plurality of groups ofplants based at least in part on plant varietal.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIG. 1 depicts an exemplary, non-limiting method for providing light toplants according to one embodiment of the invention.

FIG. 2 is a schematic top plan view of an exemplary, non-limiting growroom according to one embodiment of the invention.

FIG. 3 is a schematic side plan view of the grow room of FIG. 2 .

DESCRIPTION

Throughout the following description specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

One aspect of the invention provides a method of delivering light (e.g.photosynthetically active photons) to a plurality of plants within agrow room of an indoor farming operation while maintaining a desiredtemperature range within (and throughout) the grow room.

FIG. 1 depicts an exemplary method 100 of delivering light (e.g.photosynthetically active photons) to a plurality of plants within agrow room according to one embodiment of the invention. For the purposeof illustrating method 100, an exemplary non-limiting grow room 10 isdescribed herein.

FIGS. 2 and 3 depict an exemplary non-limiting grow room 10. It shouldbe understood that grow room 10 is presented for illustrative purposes.The description and drawings of grow room 10 provided herein are notintended to limit any aspects of a grow room for which method 100 may beemployed. For example, the description and drawings herein are notintended to limit the grow room size, grow room shape, arrangement ofracks within the grow room, arrangement of lights within the grow room,arrangement of plants within the grow room, choice of plant varietalwithin the grow room, etc.

As shown in FIGS. 2 and 3 , a plurality of plants 20 are arranged onracks 30 within grow room 10. Racks 30 may be spaced apart horizontally(e.g. in the x-direction and/or y-direction). Lights 40 may be arrangedto provide photons to each plant 20. Each light 40 may provide light toone or more plants 20.

Racks 30 may comprise any suitable racks. Each rack 30 may providemultiple rows 32 of plants 20 and lights 40. This is not mandatory. Rows32 may be stacked in the z-direction (e.g. vertically or substantiallyvertically) as shown in FIG. 3 . In the illustrated embodiment, eachrack 30 comprises four rows 32 (e.g. rows 32-1, 32-2, 32-3, 32-4). Thisis not mandatory. Each rack 30 may comprise any number of rows 32.

Plants 20 may comprise any suitable plants. Plants 20 may compriseplants of a single varietal or of multiple varietals. For example,plants 20 may comprise leafy greens (e.g. lettuce, spinach, kale, Swisschard, etc.), spices (e.g. saffron, vanilla, mustard, etc.), herbs,microgreens, vegetables (e.g. mushrooms, eggplants, squash, peppers,cucumbers, etc.), fruit (e.g. berries, tomatoes, etc.), grains (rice,wheat, corn, barley, oat, sorghum, rye, quinoa etc.), cannabis,medicinal plants, sprouts, pumpkins, etc. Plants 20 may comprise anotherplant varietal suitable for indoor farming. Plants may have nutrientsdelivered via different techniques (e.g. hydroponics, aquaponics,aeroponics, etc.). Plants 20 may be grown in a substrate medium thatcould be natural or synthetic (e.g. soil, rock wool, peat moss, coconutcoir, perlite, vermiculite, clay pebbles, rock lava, rocks,polymer-based mediums, etc.).

Lights 40 may comprise any suitable lights which producephotosynthetically active photons. Lights 40 may comprise full spectrumlights. Lights 40 may comprise LED lights. When lights 40 are turned on,lights 40 may produce heat. The heat output of lights 40 may beapproximately proportionate to the intensity of the light output oflights 40.

In the illustrated embodiments, two lights 40 are provided for eachplant 20. This not mandatory. A greater or lesser number of lights 40per plant 20 may be provided. Each light 40 may correspond to one ormore plants 20 and each plant 20 may correspond to one or more lights40. In other words, one light 40 may provide photons to a plurality ofplants and/or each plant may receive photons from a plurality of lights.

To better control which lights 40 deliver photons to which plants 20,one or more dividers, walls, curtains or the like may be provided. Forexample, one or more dividers, walls, curtains or the like may beprovided between racks 30 to prevent lights 40 on a first rack 30 fromundesirably providing photons to plants 20 on a second rack 30.Similarly, one or more dividers, walls, curtains or the like may beprovided between rows 32 to prevent lights 40 on a first row 32 fromundesirably providing photons to plants 20 on a second row 32. Suchdividers, walls, curtains or the like could even be provided within rows32 to separate plants 20 and lights 40 within a row 32.

Grow room 10 may be enclosed so as to prevent natural light or otherexterior light from entering grow room 10. The walls, windows and/orceiling of grow room 10 may be covered at least in part in a reflectivematerial such as panda film and/or insulating elements (e.g. insulationpanels).

Returning to FIG. 1 , method 100 comprises a first step 110 of obtainingor determining the desired total light integral (“TLI”) for each plant20 within grow room 10. Like DLI, TLl may be used to understand andevaluate the quantity of light a plant is receiving. Like DLI, TLI is acumulative measure of photosynthetically active radiation (“PAR”). TLImay be defined as the quantity of photosynthetically active photonsreceived by plants per area for a given time period. Unlike, DLI whichis limited to a 24 hour time period, the TLI may provide a measure ofthe quantity of light received by plants per area for a time periodother than 24 hours. However, where the time period is 24 hours, the TLIwould be equal to the DLI. The TLI may be determined based at least inpart on the DLI. The DLI and/or TLI for each plant 20 may be obtained atstep 110 by any suitable method. For example, the DLI and/or TLI may beobtained through pre-existing sources of such information or throughexperimentation. In some embodiments, the PPFD and/or photoperiod mayalso be obtained or determined at step 110.

In some embodiments, the DLI for each plant 20 within grow room 10 willbe the same or similar (e.g. each plant 20 with grow room 10 will be ofthe same varietal or varietals having the same or similar DLI and/orTLI), but this is not mandatory. Different plant varietals havingdifferent DLls, TLIs, photoperiods and/or PPFDs may be provided withingrow room 10 and/or different plant varietals having the same or similarDLls, TLIs, photoperiods and/or PPFDs may be provided within grow room10.

At step 120, each plant 20 is separated into a group 50. While plants 20in a group 50 may be physically separated from plants 20 in other groups50, this is not mandatory. Instead, plants 20 may be nominally separatedinto groups 50 such that plants 20 from one group 50 may be spread outin the x, y and/or z-directions within grow room 10 and/or separatedfrom each other by plants 20 of other groups 50.

The plants 20 of each group 50 may be chosen to achieve the followingcharacteristics:

-   each plant 20 in a group 50 has the same (or similar) photoperiod;    and-   the sum of the PPFD for all plants 20 in a group 50 is the same (or    similar) for all groups 50.

To achieve the above-noted characteristics of each group 50, plants 20may be separated into groups 50 based on a number of factors. Forexample, each plant 20 may be separated into groups 50 based on one ormore of:

-   the plant’s DLI;-   the plant’s TLI;-   the plant’s photoperiod;-   the plant’s PPFD;-   the plant’s varietal;-   the plant’s location within grow room 10;-   the total number of plants 20 within grow room 10;-   etc.

Groups 50 may be chosen such that plants 20 within a group 50 each havea photoperiod within 20% of each other, 10% of each other, 5% of eachother or less. In this way, if all plants 20 within each group 50 areprovided with light at the same time, no plant in group 50 will receivetoo many or too few hours of light.

Groups 50 may be chosen such that plants 20 within a group 50 each havea PPFD within 20% of each other, 10% of each other, 5% of each other orless. In this way, if all plants 20 within each group 50 are providedwith the same intensity of light, no plant in group 50 will receivelight that is too intense or not intense enough.

By arranging groups 50 such that the sum of the PPFD for all plants 20in a group 50 is the same (or similar) for all groups 50, energyconsumption (e.g. to power lights) and heat output (e.g. from thelights) for each group 50 may be approximately consistent. Thismaintenance of approximately consistent light (and heat) output all daymay reduce temperature fluctuations within grow room 10 and reduceoverall energy consumption. For example, by reducing temperaturefluctuations within grow room 10 due to heat generated from lights 40,the usage of heating and cooling may be reduced thereby reducing energyusage and even capital costs necessary to build grow room 10. Further,by maintaining more consistent temperatures within grow room 10, lessenergy may be required for maintaining a desired humidity within growroom 10. This effect may be rather substantial since more energy isrequired to remove moisture from cool air than from warm air andtherefore avoiding coldspots or colder periods of time may beparticularly advantageous.

Groups 50 may be chosen such that plants 20 within a group 50 each havea DLI within 20% of each other, 10% of each other, 5% of each other orless. Groups 50 may be chosen such that plants 20 within a group 50 eachhave a TLI within 20% of each other, 10% of each other, 5% of each otheror less. In this way, if all plants 20 within each group 50 are providedwith the same quantity of light, no plant in group 50 will receive toomuch or too little light.

To simplify achieving the above-noted characteristics of each group 50,each group 50 could comprise an approximately equal number of plants 20of a single varietal. This is not mandatory. Instead, groups 50 could bearranged with multiple varietals of plants 20 and different numbers ofplants 20. The number, N, of plants 20 in each group 50 may be anysuitable number. In some embodiments, the number, N, of plants in eachgroup 50 is chosen to achieve groups 50 with approximately equal ratesof heat output during the photoperiod of the plant (e.g. withapproximately equal sums of the PPFD for all plants 20 in a group 50).For example, if plants 20 of a first group 50 of plants 20 each benefitfrom a relatively lower PPFD (with relatively lower heat output perlight 40) as compared to plants 20 of a second group 50, then the firstgroup 50 may be chosen to have a greater number, N, of plants 20 ascompared to the second group 50 to achieve similar cumulative rates ofheat output per group 50. Put differently, if the PPFD of each plant 20of the first group 50 is represented by a₁ and the PPFD of each plant 20of the second group 50 is represented by a₂ where the first group has N₁plants 20 and the second group has N₂ plants 20, then the number, N₁, ofplants 20 in the first group 20 may be determined approximately asfollows:

$N_{1}\mspace{6mu} \approx \mspace{6mu}\frac{a_{2}N_{2}}{a_{1}}$

At step 120, plants 20 may be separated into any number, n, of groups50. In some embodiments, the number, n, of groups 50 is based at leastin part on the photoperiod(s) of plants 20. In some embodiments, the sumof the photoperiods of all groups 50 is approximately equal to orgreater than a time period, t. For practical reasons, the time period,t, may be 24 hours but this is not mandatory. For example, if thephotoperiod of plants 20 in each group 50 is six hours, it may bedesirable for the number, n, of groups 50 to be a multiple of four. Withfour groups and a photoperiod of six hours, each group 50 may beprovided with its DLI in series in a 24 hour period.

In some embodiments, plants 20 in each group 50 are spread throughoutgrow room 10 in the x, y and/or z-directions. Spreading plants 20 of agroup 50 around grow room 10 may facilitate even heat output of lights40 around grow room 10. As compared to arranging plants 20 of a group 50together, spreading plants 20 of a group 50 throughout grow room 10 mayreduce undesirable hot spots (e.g. where there is a greaterconcentration of lights 40 operating at a specific time in one area ofgrow room 10 than in other areas) and/or cool spots (e.g. where there isa lesser concentration of lights 40 operating at a specific time in onearea of grow room 10 than in other areas).

Plants 20 in each group 50 may be spread out by alternating racks 30and/or rows 32 within racks 30 into different groups 50. For example,every second rack 30 could be a in a first group 50 while everyremaining rack 30 is in a second group 50. As another example, everysecond row 32 of every rack 30 may be in a first group 50 while theremaining rows 32 are in a second group 50.

To facilitate spreading plants 20 within a group 50 throughout grow room10, grow room 10 may be nominally separated into sections 12. In theFIG. 2 embodiment, room 10 is nominally separated into four sections 12(section A, section B, section C and section D), each having four racks30. It should be understood that a grow room 10 may be nominallyseparated into any number of sections 12, each having one or more racks30 or portions of racks 30. While sections 12 are depicted as beingrectangular, this is not mandatory and sections 12 may be of any shape.The number, size and shape of sections 12 may be dependent on the sizeand/or shape of grow room 10 and/or the size, shape and/or number ofracks 30.

While sections 12 are depicted as including entire racks 30, this is notmandatory. Instead, a first portion of a rack 30 may be part of a firstsection 12 while a second part of a rack may be part of a second section12. For example, a section 12 could include the first rows 32-1 of someor all of the racks 30 in a grow room 10 or a section 12 could includeall of the even number rows 32-2, 32-4, etc. of some or all of the racks30 in a grow room 10. Similarly, while sections 12 are depicted and/ordescribed as including entire rows 32 of racks 30, this is notmandatory. Instead, different portions of rows could be part ofdifferent section 12. For example, a first portion of a row 32 may bepart of a first section 12 while a second portion of a row 32 may bepart of a second section 12.

To achieve a desired spread of plants 20 in each group 50 throughoutgrow room 10, plants 20 may be picked from each section 12. For example,each group 50 may comprise an equal or approximately equal number ofplants 20 from each section 12.

A similar principle may be applied to achieve a desired spread of plants20 in each group 50 at different heights. For example, each group 20 mayhave at least one plant at every row 32 height or in alternating rowsheights.

At step 130, the desired TLl is provided to each plant 20 over thecourse of a time period, t, by sequentially providing light to eachgroup 50. The desired TLI for each plant is provided sequentially on agroup-by-group basis. In some embodiments, light is providedsequentially to each group of plants 50 in a sequence that maintains thesum of PPFD in grow room 10 approximately constant throughout timeperiod, t. Time period, t, may be a 24 hour time period but this is notmandatory. In some embodiments, lights 40 of only a single group 50 ison at any given time during time period, t, such that the sum of thePPFD in grow room 10 for any given time during time period, t, isapproximately consistent. In other embodiments, lights 40 for multiplegroups may be on at the same time. In such cases, the photoperiod for afirst group 50 may overlap (in part or in whole) with the photoperiod ofone or more other groups 50. Where the photoperiods of groups 50overlap, the sequence may be chosen such that the sum of the PPFD ingrow room 10 for any given time during time period, t, is approximatelyconsistent by maintaining consistent overlap between groups 50 receivinglight. For example, if two groups 50 overlap at a given time during timeperiod, t, then the sequence may be arranged such that two groups 50substantially always (e.g. except for brief periods between photoperiodsor otherwise) overlap during time period, t.

The schedule for sequentially providing light to groups 20 may bedetermined based on a number of factors to achieve an approximatelyconstant cumulative heat output throughout time period, t (e.g. bymaintaining an approximately constant sum of PPFD within grow room 10throughout time period, t). In some embodiments, the total time of thephotoperiods of groups 50 is approximately equal to the time period, t.In such embodiments, lights 40 for each group may be turned onsequentially for their corresponding photoperiod in series. In someembodiments, the total time of the photoperiods of groups 50 is lessthan the time period, t. In such cases, there may be short periods oftime with no lights on. These short periods of time with no lights onmay be spaced apart during time period, t, to reduce the effect of suchtime periods on the temperature within grow room 10. An alternate heatsource may be turned on (or turned up) during these short periods oftime with no lights on. In some embodiments, where an alternative heatsource is also used while the lights are on, the heat output of thealternative heat source may be increased during these short periods oftime with no lights on (relative to when the lights are on). In someembodiments, the total time of the photoperiods of groups 50 is greaterthan the time period, t. In such cases, there may be overlap (in wholeor in part) of photoperiods of different groups 50.

In some embodiments, rather than provide lights 40 that are turned onfor some periods of time and turned off for other periods of time, asmaller number of lights 40 that are always turned on (or turned on mostof the time) is employed by moving lights 40 from group 50 to group 50and/or moving groups 50 to lights 40. By moving lights 40 and/or plants20, the same number of lights 40 may be turned on at all times which mayresult in a approximately constant rate of heat output from lights 40.

Plants 20 may be placed on a conveyor system (e.g. a conveyor belt, ahanging conveyor, a water-based conveyor or the like). Plants 20 in agroup 50 may then be moved under lights 40 to achieve the desired TLland then moved away from lights 40 when the desired TLl is achieved tomake way for another group 50 of plants 20. The achieved TLl of plants20 may therefore be controlled by the speed or interval at which theyare moved under lights 40, the intensity of lights 40, etc.

Lights 40 may be placed on a conveyor system (e.g. a hanging conveyor orthe like). Lights 40 may then be moved over a group 50 of plants 20 toachieve the desired TLl and then moved away from that group 50 when thedesired TLl is achieved. Lights 40 may then be moved over another group50 of plants 20. The achieved TLl of plants 20 may therefore becontrolled by the speed or interval at which lights 40 are moved, theintensity of lights 40, etc.

In some embodiments, both lights 40 and plants 20 are arranged to bemoveable to facilitate providing the desired TLl to plants 20.

To better illustrate method 100, a series of exemplary scenarios forgrow room 10 are provided. These scenarios are meant to be illustrativeonly and are not intended to limit method 100 in any way. For thepurpose of simplifying the following scenarios, it may be assumed thateach row 32 of each rack 30 comprises the same number of plants 20 andthe same number of lights 40. However, it should be understood that inpractice, each row 32 may have different numbers of plants 20 and/orlights 40. Moreover, while the following scenarios are based on growroom 10 for FIGS. 2 and 3 , it should be understood that the scenarioscould be modified for different grow rooms 10 described herein orotherwise. Further, while each of the following scenarios rely onturning lights 40 on and off, it should be understood that lights 40and/or plants 20 could be moveable to avoid turning lights on and off.

Exemplary Scenario 1

In a first exemplary scenario, all plants 20 have a same or similar TLIand have a photoperiod of 12 hours. Plants 20 are nominally separatedinto a first group comprising all of plants 20 within racks A1, A3, B1,B3, C1, C3, D1 and D3 and a second group comprising all of plants 20within racks A2, A4, B2, B4, C2, C4, D2 and D4. In this way, there is anapproximately equal number of plants 20 of each group 50 in each section12 and at each row height.

A time period, t, of 24 hours is separated into a first sub-period of 12hours and a second sub-period of 12 hours. During the first sub-period,lights 40 for the first group of plants 20 are turned on while lights 40for the second group of plants 20 are turned off. During the secondsub-period, lights 40 for the second group of plants 20 are turned onwhile lights 40 for the first group of plants 20 are turned off.

In the first exemplary scenario, the same number of lights 40 are turnedon with the same intensity at all times during time period, t. Moreover,since plants 20 of each of the first and second groups 50 are spreadapart around grow room 10 (in the x, y and z-directions), a likelihoodof hotspots (due to heat from lights 40 that are turned on) or coldspots(due to a lack of heat from lights 40 that are turned off) within growroom 10 is reduced.

Exemplary Scenario 2

In a second exemplary scenario, all plants 20 have a same or similar TLIand have a photoperiod of 12 hours. Plants 20 are nominally separatedinto a first group comprising all of plants 20 within even-numbered rowsof racks (e.g. all plants on rows 32-2 and 32-4 in grow room 10) and asecond group comprising all of plants 20 within odd-numbered rows racks(e.g. all plants on rows 32-1 and 32-3 in grow room 10). In this way,there is an approximately equal number of plants 20 of each group 50 ineach section 12 and at each row height.

A time period, t, of 24 hours is separated into a first sub-period of 12hours and a second sub-period of 12 hours. During the first sub-period,lights 40 for the first group of plants 20 are turned on while lights 40for the second group of plants 20 are turned off. During the secondsub-period, lights 40 for the second group of plants 20 are turned onwhile lights 40 for the first group of plants 20 are turned off.

In the second exemplary scenario, the same number of lights 40 areturned on with the same intensity at all times during time period, t.Moreover, since plants 20 of each of the first and second groups 50 arespread apart around grow room 10 (in the x, y and z-directions), alikelihood of hotspots (due to heat from lights 40 that are turned on)or coldspots (due to a lack of heat from lights 40 that are turned off)within grow room 10 is reduced.

Exemplary Scenario 3

In a third exemplary scenario, all plants 20 have a same or similar TLIand have a photoperiod of 6 hours. Plants 20 are nominally separatedinto a first group comprising all plants 20 on rows 32-1 and 32-3 ofracks A1, A3, B1, B3, C1, C3, D1 and D3, a second group comprising allplants 20 on rows 32-2 and 32-4 of racks A1, A3, B1, B3, C1, C3, D1 andD3, a third group comprising all plants 20 on rows 32-1 and 32-3 ofracks A2, A4, B2, B4, C2, C4, D2 and D4 and a fourth group comprisingall plants 20 on rows 32-2 and 32-4 of racks A2, A4, B2, B4, C2, C4, D2and D4. In this way, there is an approximately equal number of plants 20of each group 50 in each section 12 and at each row height.

A time period, t, of 24 hours is separated into a first sub-period of 6hours, a second sub-period of 6 hours, a third sub-period of 6 hours anda fourth sub-period of 6 hours. During the first sub-period, lights 40for the first group of plants 20 are turned on while lights 40 for thesecond, third and fourth groups of plants 20 are turned off. During thesecond sub-period, lights 40 for the second group of plants 20 areturned on while lights 40 for the first, third and fourth groups ofplants 20 are turned off. During the third sub-period, lights 40 for thethird group of plants 20 are turned on while lights 40 for the first,second and fourth groups of plants 20 are turned off. During the fourthsub-period, lights 40 for the fourth group of plants 20 are turned onwhile lights 40 for the first, second and third groups of plants 20 areturned off.

As in the first exemplary scenario, the same number of lights 40 areturned on with the same intensity at all times during time period, t.Moreover, since plants 20 of each of the first, second, third and fourthgroups 50 are spread apart around grow room 10 (in the x, y andz-directions), a likelihood of hotspots (due to heat from lights 40 thatare turned on) or coldspots (due to a lack of heat from lights 40 thatare turned off) within grow room 10 is reduced.

Exemplary Scenario 4

In a fourth exemplary scenario, all plants 20 have a same or similar TLIand have a photoperiod of 12 hours. Plants 20 are nominally separatedinto a first group comprising all plants 20 on rows 32-1 of all racks ingrow room 10, a second group comprising a all plants 20 on rows 32-2 ofall racks in grow room 10, a third group comprising all plants 20 onrows 32-3 of all racks in grow room 10 and a fourth group comprising allplants 20 on rows 32-4 of all racks in grow room 10. In this way, thereis an approximately equal number of plants 20 of each group 50 in eachsection 12.

A time period, t, of 24 hours is separated into a first sub-period of 6hours, a second sub-period of 6 hours, a third sub-period of 6 hours anda fourth sub-period of 6 hours. During the first sub-period, lights 40for the first and fourth groups of plants 20 are turned on while lights40 for the second, and third groups of plants 20 are turned off. Duringthe second sub-period, lights 40 for the first and second groups ofplants 20 are turned on while lights 40 for the third and fourth groupsof plants 20 are turned off. During the third sub-period, lights 40 forthe second and third groups of plants 20 are turned on while lights 40for the first and fourth groups of plants 20 are turned off. During thefourth sub-period, lights 40 for the third and fourth groups of plants20 are turned on while lights 40 for the first and second groups ofplants 20 are turned off.

As in the first exemplary scenario, the same number of lights 40 areturned on with the same intensity at all times during time period, t.Moreover, since plants 20 of each of the first, second, third and fourthgroups 50 are spread apart around grow room 10 (in the x andy-directions), a likelihood of hotspots (due to heat from lights 40 thatare turned on) or coldspots (due to a lack of heat from lights 40 thatare turned off) within grow room 10 is reduced.

Exemplary Scenario 5

In a fifth exemplary scenario, plants 20 are of two different varietals.The TLl for each plant is approximately equal but the first plantvarietal has a photoperiod of 12 hours and the second varietal has aphotoperiod of 6 hours. Plants 20 are nominally separated into a firstgroup comprising plants 20 of the first varietal arranged on rows racksA1, B1, C1 and D1, a second group comprising plants 20 of the firstvarietal arranged on racks A2, B2, C2 and D2, a third group comprisingplants 20 of the second varietal arranged on rows 32-1 and 32-3 of racksA3, B3, C3 and D3, a fourth group comprising plants 20 of the secondvarietal arranged on rows 32-2 and 32-4 of racks A3, B3, C3 and D3, afifth group comprising plants 20 of the second varietal arranged on rows32-1 and 32-3 of racks A4, B4, C4 and D4 and a sixth group comprisingplants 20 of the second varietal arranged on rows 32-2 and 32-4 of racksA4, B4, C4 and D4.

A time period, t, of 24 hours is separated into a first sub-period of 6hours, a second sub-period of 6 hours, a third sub-period of 6 hours anda fourth sub-period of 6 hours. During the first sub-period, lights 40for the first and third groups of plants 20 are turned on while lights40 for the second, fourth, fifth and sixth groups of plants 20 areturned off. During the second sub-period, lights 40 for the first andfourth groups of plants 20 are turned on while lights 40 for the third,fourth, fifth and sixth groups of plants 20 are turned off. During thethird sub-period, lights 40 for the second and fifth groups of plants 20are turned on while lights 40 for the first, third, fourth and sixthgroups of plants 20 are turned off. During the fourth sub-period, lights40 for the second and sixth groups of plants 20 are turned on whilelights 40 for the first, third, fourth and fifth groups of plants 20 areturned off.

Despite the presence of multiple varietals with different photoperiods,the same number of lights 40 are turned on with the same intensity atall times during time period, t. Moreover, since plants 20 of each ofthe first, second, third and fourth groups 50 are spread apart aroundgrow room 10 (in the x, y and z-directions), a likelihood of hotspots(due to heat from lights 40 that are turned on) or coldspots (due to alack of heat from lights 40 that are turned off) within grow room 10 isreduced.

Exemplary Scenario 6

In a sixth exemplary scenario, plants 20 are of two different varietals.The first plant varietal has a PPFD of half that of the second varietal.Both varietals have a photoperiod of 8 hours. Plants 20 are nominallyseparated into a first group comprising plants 20 of the first varietalarranged on rows 32-1 and 32-3 of all racks in grow room 10, a secondgroup comprising plants 20 of the second varietal arranged on rows 32-2of all racks in grow room 10 and a third group comprising plants 20 ofthe second varietal arranged on rows 32-4 of all racks in grow room 10.

A time period, t, of 24 hours is separated into a first sub-period of 8hours, a second sub-period of 8 hours and a third sub-period of 8 hours.During the first sub-period, lights 40 for the first group of plants 20are turned on while lights 40 for the second and third groups of plants20 are turned off. During the second sub-period, lights 40 for thesecond group of plants 20 are turned on while lights 40 for the firstand third groups of plants 20 are turned off. During the thirdsub-period, lights 40 for the third group of plants 20 are turned onwhile lights 40 for the first and second groups of plants 20 are turnedoff.

Despite the presence of multiple varietals with different PPFDs, anddifferent numbers of lights 40 turned on at different times during timeperiod, t, the cumulative heat output of lights 40 is maintainedapproximately constant by having half the number of lights at twice theintensity during the second and third sub-periods as compared to thefirst sub-period. Moreover, since plants 20 of each of the first,second, third and fourth groups 50 are spread apart around grow room 10(in the x, y and/or z-directions), a likelihood of hotspots (due to heatfrom lights 40 that are turned on) or coldspots (due to a lack of heatfrom lights 40 that are turned off) within grow room 10 is reduced.

Interpretation of Terms

Unless the context clearly requires otherwise, throughout thedescription and the claims:

-   “comprise”, “comprising”, and the like are to be construed in an    inclusive sense, as opposed to an exclusive or exhaustive sense;    that is to say, in the sense of “including, but not limited to”;-   “connected”, “coupled”, or any variant thereof, means any connection    or coupling, either direct or indirect, between two or more    elements; the coupling or connection between the elements can be    physical, logical, or a combination thereof; elements which are    integrally formed may be considered to be connected or coupled;-   “herein”, “above”, “below”, and words of similar import, when used    to describe this specification, shall refer to this specification as    a whole, and not to any particular portions of this specification;-   “or”, in reference to a list of two or more items, covers all of the    following interpretations of the word: any of the items in the list,    all of the items in the list, and any combination of the items in    the list;-   the singular forms “a”, “an”, and “the” also include the meaning of    any appropriate plural forms.

Words that indicate directions such as “vertical”, “transverse”,“horizontal”, “upward”, “downward”, “forward”, “backward”, “inward”,“outward”, “vertical”, “transverse”, “left”, “right”, “front”, “back”,“top”, “bottom”, “below”, “above”, “under”, and the like, used in thisdescription and any accompanying claims (where present), depend on thespecific orientation of the apparatus described and illustrated. Thesubject matter described herein may assume various alternativeorientations. Accordingly, these directional terms are not strictlydefined and should not be interpreted narrowly.

Although the operations of the method(s) herein are shown and describedin a particular order, the order of the operations of each method may bealtered so that certain operations may be performed in an inverse orderor so that certain operation may be performed, at least in part,concurrently with other operations. In another embodiment, instructionsor sub-operations of distinct operations may be in an intermittentand/or alternating manner.

Where a component is referred to above, unless otherwise indicated,reference to that component (including a reference to a “means”) shouldbe interpreted as including as equivalents of that component anycomponent which performs the function of the described component (i.e.that is functionally equivalent), including components which are notstructurally equivalent to the disclosed structure which performs thefunction in the illustrated exemplary embodiments of the invention.

Various features are described herein as being present in “someembodiments”. Such features are not mandatory and may not be present inall embodiments. Embodiments of the invention may include zero, any oneor any combination of two or more of such features. This is limited onlyto the extent that certain ones of such features are incompatible withother ones of such features in the sense that it would be impossible fora person of ordinary skill in the art to construct a practicalembodiment that combines such incompatible features. Consequently, thedescription that “some embodiments” possess feature A and “someembodiments” possess feature B should be interpreted as an expressindication that the inventors also contemplate embodiments which combinefeatures A and B (unless the description states otherwise or features Aand B are fundamentally incompatible).

While a number of exemplary aspects and embodiments have been discussedabove, those of skill in the art will recognize certain modifications,permutations, additions and sub-combinations thereof. It is thereforeintended that the following appended claims and claims hereafterintroduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are consistent with thebroadest interpretation of the specification as a whole.

Specific examples of systems, methods and apparatus have been describedherein for purposes of illustration. These are only examples. Thetechnology provided herein can be applied to systems other than theexample systems described above. Many alterations, modifications,additions, omissions, and permutations are possible within the practiceof this invention. This invention includes variations on describedembodiments that would be apparent to the skilled addressee, includingvariations obtained by: replacing features, elements and/or acts withequivalent features, elements and/or acts; mixing and matching offeatures, elements and/or acts from different embodiments; combiningfeatures, elements and/or acts from embodiments as described herein withfeatures, elements and/or acts of other technology; and/or omittingcombining features, elements and/or acts from described embodiments.

1. A method of providing light to plants, the method comprising:providing a plurality of plants within a room; grouping each plant ofthe plurality of plants into one of a plurality of groups of plantsbased at least in part on a desired total light integral (“TLI”) foreach of the plurality of plants for a time period; providing thecorresponding desired TLI to each plant of the plurality of plants bysequentially providing light to each of the plurality of groups ofplants during the time period; wherein for each group of plants: eachplant has an approximately similar photoperiod; and a sum of thephotosynthetic photon flux densities (“PPFDs”) of all plants in thegroup of plants is approximately the same.
 2. A method according toclaim 1 comprising grouping each light of a plurality of lights into oneof a plurality of groups of lights wherein each group of lightscorresponds to one of the plurality of groups of plants within the room.3. A method according to claim 2 wherein each group of lights isarranged to provide photons substantially only to its correspondinggroup of plants.
 4. A method according to claim 2 comprising maintaininga cumulative rate of heat output of the plurality of lightsapproximately constant during the time period.
 5. A method according toclaim 2 wherein sequentially providing light to each of the plurality ofgroups of plants during a time period comprises sequentially turning oneach group of lights of the plurality of groups of lights for asub-period of time.
 6. A method according to claim 5 wherein at leastsome of the sub-periods of time overlap.
 7. A method according to claim5 wherein each of the sub-periods of time is approximately equal inmagnitude.
 8. A method according to claim 5 wherein at least two of thesub-periods of time have different magnitudes.
 9. A method according toclaim 5 wherein the combined magnitude of the sub-periods of time isapproximately equal to the time period.
 10. A method according to claim5 wherein each group of lights is turned on only once during the timeperiod.
 11. A method according to claim 5 wherein one or more groups oflights is turned on multiple times during the time period.
 12. A methodaccording to claim 2 wherein sequentially providing light to each of theplurality of groups of plants during a time period comprises selectivelyturning on a first group of lights of the plurality of groups of lightsfor a first sub-period of time while selectively turning off a secondgroup of lights of the plurality of groups of lights for the firstsub-period of time.
 13. A method according to claim 2 whereinsequentially providing light to each of the plurality of groups ofplants during a time period comprises: selectively turning on a firstgroup of lights of the plurality of groups of lights for a firstsub-period of time while selectively turning off a second group oflights of the plurality of groups of lights for the first sub-period oftime; and selectively turning on the second group of lights for a secondsub-period of time while selectively turning off the first group oflights for the second sub-period of time.
 14. A method according toclaim 13 wherein the combined magnitude of the first and secondsub-periods of time is approximately equal to the magnitude of the timeperiod.
 15. A method according to claim 1 wherein a plurality of lightsare moveable between a plurality of locations and in each location theplurality of lights provides photos to a corresponding a group of plantsof the plurality of plants within the room.
 16. A method according toclaim 15 wherein in each location, the plurality of lights are arrangedto provide photons substantially only to the corresponding group ofplants.
 17. A method according to claim 1 wherein at least one of thegroups of plants is arranged across rows of multiple racks.
 18. A methodaccording to claim 17 wherein at least one of the groups of plants isarranged across rows of multiple racks at the same height.
 19. A methodaccording to claim 1 wherein at least one of the groups of plantscomprises plants spaced apart throughout the room.
 20. A methodaccording to claim 1 wherein the time period is approximately equal to24 hours.
 21. A method according to claim 1 wherein the room is arrangedto substantially prevent external light from entering the room.
 22. Amethod according to claim 1 wherein for each group of plants, thephotoperiods of the plants of said group vary by less than 20%.
 23. Amethod according to claim 1 wherein the sum of the PPFDs for each groupvaries by less than 20%.
 24. A method according to claim 1 wherein theplurality of plants comprises at least two different plant varietals.25. A method according to claim 24 comprising grouping each of theplurality of plants into the plurality of groups of plants based atleast in part on plant varietal.